Safety meters and smart meter equipment that meet high electric shock protection requirements

Abstract

The invention relates to a safety electric meter and intelligent electric meter equipment that meet the requirements of high electric shock protection, which comprises an outer shell and a bottom shell that are connected to each other; a PCB and electronic devices are installed in the bottom shell, and a shielding cover with a plurality of welding feet is arranged between the PCB and the electronic devices and the outer shell; the shielding cover is buckled on the PCB and the electronic devices in a conformal manner; a PCB live wire conduction area is arranged on the periphery of the upper surface of the PCB and the electronic devices to be electrically connected with the live wires of the PCB and the electronic devices; the shielding cover is installed in the gap between the outer shell and the PCB and the electronic devices and is made of a metal conductive material; the distance from the high-voltage contact on the upper surface of the shielding cover to the top wall of the outer shell is smaller than the distance from the protection contact to the top wall of the outer shell; the shielding cover is welded to the live wire conduction area of ​​the PCB through welding feet to achieve conduction with the live wire; the invention has reasonable design, compact structure and convenient use.

Description

Technical Field

[0001] The present invention relates to a safe electric meter and an intelligent electric meter device that meet the requirements of high electric shock protection, meet the requirements of high electric shock (air discharge) protection of the electric meter, realize comprehensive protection, safe use and convenient observation. Background Art

[0002] Traditional electric meters solve the problem of electric shock protection by increasing the creepage distance between the internal components of the meter and the outer surface of the shell. However, this method of increasing the distance is more suitable for conventional (such as 15KV) electric shock requirements. If high electric shock (such as 35KV) protection is also designed in this way, it will often cause the meter to be too large and the effect is not ideal, which cannot meet the market requirements. The present invention is an effective solution to the high electric shock protection requirements.

[0003] At present, it is inconvenient to check the electricity meter and it needs to be illuminated by a flashlight. Summary of the invention

[0004] The technical problem to be solved by the present invention is generally to provide a safe electric meter that meets high electric shock protection requirements.

[0005] To solve the above problems, the technical solution adopted by the present invention is:

[0006] A safety electric meter that meets high electric shock protection requirements comprises an outer shell and a bottom shell that are connected to each other; a PCB and electronic components are installed in the bottom shell.

[0007] A shielding cover having a plurality of solder pins is arranged between the PCB and the electronic device and the housing; the shielding cover is conformally buckled on the PCB and the electronic device;

[0008] A PCB live wire conduction area is provided on the periphery of the upper surface of the PCB and the electronic device to be electrically connected to the live wire of the PCB and the electronic device;

[0009] The shielding cover is installed in the gap between the housing and the PCB and the electronic components and is made of a metal conductive material; the distance from the high-voltage contact on the upper surface of the shielding cover to the top wall of the housing is smaller than the distance from the protection contact to the top wall of the housing;

[0010] The shielding cover is welded to the live wire conduction area of ​​the PCB through welding feet to achieve conduction with the live wire.

[0011] As a further improvement of the above technical solution:

[0012] Chips and capacitors are arranged on the PCB and electronic devices;

[0013] The shielding cover has a central control rectangular hole corresponding to the chip and a capacitor hole corresponding to the capacitor, and an L-shaped bent plate with a protective contact is provided on the shielding cover;

[0014] A T-shaped bend is provided at the lower end of the welding foot.

[0015] A display screen and buttons are arranged on the shell; a plug-in hole is arranged on the live wire conduction area of ​​the PCB for inserting the T-bend.

[0016] A smart electric meter device, comprising a safety electric meter and an open meter box for placing the safety electric meter;

[0017] A backlight circuit is provided on the safety electric meter for lighting;

[0018] The meter box has an anti-interference detection circuit to prevent the interference signal from the switching power supply from being coupled to the detection end when the electric energy meter is powered on, thereby affecting the final detection result.

[0019] The invention has reasonable design, low cost, durability, safety and reliability, simple operation, time and labor saving, money saving, compact structure and convenient use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the use structure of the present invention.

[0021] Figure 2 It is a structural schematic diagram of the present invention.

[0022] Figure 3 It is a circuit diagram of the present invention.

[0023] Figure 4 This is a schematic diagram of the practical single-chip microcomputer signal input circuit.

[0024] Figure 5 It is a schematic diagram of the analog switch module circuit of the present invention.

[0025] Figure 6 It is a schematic diagram of the signal output circuit of the present invention.

[0026] Figure 7 It is a schematic diagram of a power-on detection circuit of the present invention.

[0027] Among them: 1. Display screen; 2. Button; 3. Shell; 4. Shielding cover; 5. Solder pins; 6. PCB and electronic devices; 7. PCB live wire conduction area; 8. Bottom shell; 9. Central control rectangular hole; 10. Capacitor hole; 11. L-shaped bending plate; 12. Chip; 13. Protective contacts; 14. T-shaped bending; 15. Capacitor components; 16. High voltage electric shock. DETAILED DESCRIPTION

[0028] As an example of lightning protection, Figure 1-2This embodiment comprises a housing (3) and a bottom housing (8) which are connected to each other; a PCB and an electronic device (6) are installed in the bottom housing (8), and a display screen (1) and a button (2) are arranged on the housing (3);

[0029] A shielding cover (4) having a plurality of solder pins (5) is arranged between the PCB and the electronic device (6) and the housing (3); the shielding cover (4) is conformally buckled onto the PCB and the electronic device (6);

[0030] A PCB live wire conduction area (7) is provided on the periphery of the upper surface of the PCB and the electronic device (6) to be electrically connected to the live wire of the PCB and the electronic device (6);

[0031] A chip (12) and a capacitor (15) are arranged on the PCB and the electronic device (6);

[0032] The shielding cover (4) has a central control rectangular hole (9) corresponding to the chip (12) and a capacitor hole (10) corresponding to the capacitor element (15), and an L-shaped bent plate (11) having a protective contact (13) is arranged on the shielding cover (4);

[0033] A T-shaped bend (14) is provided at the lower end of the welding foot (5).

[0034] The shielding cover (4) is installed in the gap between the housing (3) and the PCB and the electronic device (6) and is made of a metal conductive material; the distance between the high-voltage contact (16) on the upper surface of the shielding cover (4) and the top wall of the housing (3) is smaller than the distance between the protection contact (13) and the top wall of the housing (3).

[0035] The shielding cover (4) is welded to the live wire conducting area (7) of the PCB via welding feet (5) to achieve conduction with the live wire;

[0036] A plug-in hole is provided on the PCB live wire conduction area (7) for inserting a T-shaped bend (14).

[0037] When the front of the housing (3) is subjected to electric shock, the electricity can be conducted to the live wire through the shielding cover (4); when the side seam between the housing (3) and the bottom shell (8) is subjected to electric shock, the electricity can be directly conducted to the live wire from the PCB live wire conducting area (7), thereby preventing other components from being subjected to electric shock and achieving an overall high-strength electrical protection effect.

[0038] As an example of a lighting circuit, Figure 3As an improvement point, the circuit designed this time includes a series-connected chip LED lamp DD81-DD83, resistors RD83-RD85 and a transistor QD81; the output end of the series-connected chip LED lamp DD81-DD83 is electrically connected to the collector of the transistor QD81 through the resistor RD85; this embodiment is used to solve the problem of uneven backlight brightness and occasional malfunction of transistors in the backlight drive amplifier circuit used for the electric energy meter.

[0039] The positive electrode of the SMD LED lamp DD81 is electrically connected to the input voltage of the constant current source circuit. The input voltage is HVDD output by the power chip or rectified by the transformer.

[0040] One end of the resistor RD84 is electrically connected to the microcontroller control signal Back Light Control, and the other end is connected to the base of the transistor QD81. The emitter of the transistor QD81 is connected to the ground through the resistor RD83.

[0041] When the MCU control signal Back Light Control voltage is powered on, the MCU outputs a high level control signal to turn on the transistor, and the SMD LED is lit. The resistance values ​​of RD85 and RD83 need to be set in the parameters so that the current in the emitter path of the transistor QD81 is less than the current in the collector path, achieving a constant current effect.

[0042] As an extension, transistor QD81 can be a MOS tube; resistors RD85 and RD8 are adjustable variable resistors. SMD LED lamps DD81-DD83 are electromagnetic or adhesive.

[0043] The constant current source backlight circuit of the present invention has a constant current, and the triode works in the saturation region and is used as a switch; the present invention has a reasonable design, low cost, durability, safety and reliability, simple operation, time and labor saving, money saving, compact structure and convenient use. The circuit of the present invention has a large power supply voltage, and can drive multiple transistors at the same time; after being greater than the conduction voltage drop of the diode, the constant current source, the current does not change with the change of voltage; the backlight brightness is uniform; the response speed is fast, and it can work stably for a long time.

[0044] like Figure 4-7 , as an embodiment of the anti-interference circuit, the present invention comprises three modules and four circuits, including an analog switch module, a power-on detection module and a power-off detection module;

[0045] Among them, the power-off detection module includes a single-chip microcomputer signal input circuit and a detection signal output circuit. Two detection electrodes R+ are arranged between the single-chip microcomputer signal input circuit and the detection signal output circuit for signal transmission. Under normal circumstances, the two detection electrodes R+ of the electric energy meter should be in a short-circuited state.

[0046] The analog switch module includes an integrated circuit UT1, wherein the IN pin 1 is connected to the electric energy meter DVDD as an enable pin input control signal; the normally closed pin 2 is connected to the output signal of the power-off detection module;

[0047] Pin 3 of the integrated circuit UT1 is connected to the GND of the electric energy meter; the power supply pin 4 is connected to the MVDD end of the electric energy meter. When powered on, the MVDD is output through a DC-DC power supply, and when powered off, the MVDD is powered by a battery. The power supply pin 4 is grounded through a capacitor CT11; the normally open pin 5 is connected to the output signal of the power-on detection module; the common terminal 6 is connected to the microcontroller through a resistor.

[0048] When powered on, DVDD is output through DC-DC, and the IN pin controls the analog switch to output a normally open pin signal. The microcontroller detects the meter box status when the electricity meter is powered on. After power failure, the analog switch outputs a normally closed pin signal, and the microcontroller detects the meter box status when the power is off.

[0049] The power-on detection circuit includes an optocoupler DT3, resistors RT2, RT3, RT4, RT6, a capacitor CT10, a diode DT4 and a transistor QT2;

[0050] Pin 1 of the front end of the optocoupler DT3 is electrically connected to a 5V power supply, and the resistor RT6 and the capacitor CT10 are connected in parallel as a filter, with one end connected to the 5V power supply, and the other end and one end of the resistor RT4 are connected together to pin 2 of the optocoupler DT3, the other end of the resistor RT4 is connected to the positive electrode of the diode DT4, and the negative electrode of the diode DT is connected to the positive electrode R+ of the detection terminal; pin 3 of the rear end of the optocoupler DT3 is connected to DVDD, and one end of the resistor RT3 connected in parallel with the resistor RT2 is connected to pin 4 of the optocoupler, the other end of the resistor RT2 is connected to the ground, and the other end of the resistor RT3 is connected to the base of the transistor QT2, the collector of the transistor is connected to the power-on meter box open detection signal MeterBox Cover Open Test P, and the emitter is connected to the ground.

[0051] When the output signal of the power-on detection module of the two detection electrodes is pulled low, the analog switch outputs a low level, the microcontroller receives the low level, and no meter box opening event occurs. When the detection electrode is disconnected, the optocoupler cannot be turned on, the output signal of the power-on detection module is pulled to a high level through the resistor, the microcontroller detects the high level, and records the meter box opening event.

[0052] In the power-off detection circuit,

[0053] The single chip computer signal input circuit includes resistors RT8-RT10, PMOS tube QT4, Y capacitor CT3 and unidirectional TVS tube DT2;

[0054] One end of the resistor RT10 is connected to the microcontroller input signal MeterBox cover Open Test Ctl, and the other end is connected to the gate of the PMOS tube QT4 with one end of the resistor RT9. The other end of the resistor RT9 and MVDD are connected to the source of the PMOS tube QT4. The resistor RT8 is connected in parallel with the TVS tube DT2, and the positive electrode of the TVS tube DT2 is grounded. The negative electrode of the TVS tube DT2 and one end of the Y capacitor CT3 are connected to the drain of the PMOS tube QT4. The other end of the Y capacitor CT3 is connected to the detection electrode R+.

[0055] The signal output circuit includes transistor QT1, resistor RT5, capacitors CT1, CT2 and diodes DT1, DT5; the cathode of diode DT5 is connected to MGND, and the anode of diode DT5 is electrically connected to air switch MB1 and one end of Y capacitor CT2 respectively; after resistor RT5 is connected in parallel with capacitor CT1, one end is connected to the base of transistor QT1 together with the cathode of diode DT1 and the other end of Y capacitor CT2, the other end of resistor RT5 is connected in parallel with capacitor CT1, the anode of diode DT1 and the emitter of transistor QT1 are connected to GND, and the collector of transistor QT1 is connected to the normally closed pin MeterBox cover Open Test NP of analog switch, and is pulled to a high level through the analog switch.

[0056] When the MCU detects the power-off state, it will send out a square wave with a fixed period. The square wave is turned on through the PMOS tube QT4 of the MCU signal input circuit. When the two detection poles are short-circuited, the Y capacitor CT3 can conduct the AC signal. The signal is transmitted to the signal output circuit. The resistor RT5 and the capacitor CT1 will filter the signal. When the transistor QT1 is turned on, the signal on the normally closed pin will change accordingly. The MCU will receive the signal of the corresponding period, and no meter box opening event will occur. When the two detection poles are disconnected, the detection module cannot receive the square wave signal input by the MCU, and the MCU records the meter box opening event.

[0057] The analog switch of this embodiment performs output signal control, and uses the analog switch to eliminate the influence of the switching power supply on the signal. It has reasonable design, low cost, strong durability, safety and reliability, simple operation, time saving, labor saving, money saving, compact structure and convenient use. The present invention uses the analog switch to realize the detection of upper and lower power separately to realize the power-on interference suppression, which has low cost, high sensitivity, strong adaptability and practicality. The present invention is fully described for a clearer disclosure, and the prior art will not be listed one by one.

[0058] As an integrated Figure 1-7 , a smart meter device of the present invention comprises a safety meter and an open meter box for placing the safety meter;

[0059] A backlight circuit is provided on the safety electric meter for lighting;

[0060] The meter box has an anti-interference detection circuit to prevent the interference signal from the switching power supply from being coupled to the detection end when the electric energy meter is powered on, thereby affecting the final detection result.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents; it is obvious for those skilled in the art to combine multiple technical solutions of the present invention. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention. The technical contents not described in detail in the present invention are all known technologies.

Claims

1. A safety electric meter that meets high electric shock protection requirements, characterized in that: It comprises an outer shell (3) and a bottom shell (8) which are connected to each other; a PCB and an electronic device (6) are installed in the bottom shell (8); A shielding cover (4) having a plurality of solder pins (5) is arranged between the PCB and the electronic device (6) and the housing (3); the shielding cover (4) is conformally buckled onto the PCB and the electronic device (6); A PCB live wire conduction area (7) is provided on the periphery of the upper surface of the PCB and the electronic device (6) to be electrically connected to the live wire of the PCB and the electronic device (6); The shielding cover (4) is installed in the gap between the housing (3) and the PCB and the electronic device (6) and is made of a metal conductive material; The distance between the high-voltage contact (16) on the upper surface of the shielding cover (4) and the top wall of the housing (3) is smaller than the distance between the protection contact (13) and the top wall of the housing (3); The shielding cover (4) is welded to the live wire conducting area (7) of the PCB via welding feet (5) to achieve conduction with the live wire; A chip (12) and a capacitor (15) are arranged on the PCB and the electronic device (6); The shielding cover (4) has a central control rectangular hole (9) corresponding to the chip (12) and a capacitor hole (10) corresponding to the capacitor element (15), and an L-shaped bent plate (11) having a protective contact (13) is arranged on the shielding cover (4); A display screen (1) and a button (2) are arranged on the housing (3); a T-shaped bend (14) is arranged at the lower end of the soldering foot (5); and a plug hole is arranged on the PCB live wire conduction area (7) for inserting the T-shaped bend (14).

2. A smart meter device, characterized in that: It comprises the safety electric meter as claimed in claim 1 and an open meter box for placing the safety electric meter; A backlight circuit is provided on the safety electric meter for lighting; The open meter box has a detection anti-interference circuit to prevent the interference signal from the switching power supply from coupling to the detection end when the electric energy meter is powered on, thus affecting the final detection result; The backlight circuit includes a series of SMD LED lamps DD81-DD83, resistors RD83-RD85 and a transistor QD81; the output end of the series of SMD LED lamps DD81-DD83 is electrically connected to the collector of the transistor QD81 through the resistor RD85; The positive electrode of the SMD LED lamp DD81 is electrically connected to the input voltage of the constant current source circuit. The input voltage is HVDD output by the power chip or rectified by the transformer. One end of the resistor RD84 is electrically connected to the microcontroller control signal Back Light Control, and the other end is connected to the base of the transistor QD81. The emitter of the transistor QD81 is connected to the ground through the resistor RD83. When the MCU control signal Back Light Control voltage is powered on, the MCU outputs a high level control signal to turn on the transistor, and the SMD LED is lit. The resistance values ​​of RD85 and RD83 need to be set in the parameters so that the current in the emitter path of the transistor QD81 is less than the current in the collector path, achieving a constant current effect. The detection anti-interference circuit includes three modules and four circuits, including an analog switch module, a power-on detection module and a power-off detection module; Among them, the power-off detection module includes a single-chip signal input circuit and a detection signal output circuit. Two detection electrodes R+ are arranged between the single-chip signal input circuit and the detection signal output circuit for signal transmission. Under normal circumstances, the two detection electrodes R+ of the electric energy meter should be in a short-circuited state; The analog switch module includes an integrated circuit UT1, wherein the IN pin 1 is connected to the electric energy meter DVDD as an enable pin input control signal; the normally closed pin 2 is connected to the output signal of the power-off detection module; Pin 3 of the integrated circuit UT1 is connected to the GND of the electric energy meter; the power supply pin 4 is connected to the MVDD end of the electric energy meter. When powered on, the MVDD is output through a DC-DC power supply, and when powered off, the MVDD is powered by a battery. The power supply pin 4 is grounded through a capacitor CT11; the normally open pin 5 is connected to the output signal of the power-on detection module; the common terminal 6 is connected to the microcontroller through a resistor; When powered on, DVDD is output through DC-DC, and the IN pin controls the analog switch to output a normally open pin signal. The microcontroller detects the meter box status when the energy meter is powered on. After power failure, the analog switch outputs a normally closed pin signal, and the microcontroller detects the meter box status when the power is off. The power-on detection circuit includes an optocoupler DT3, resistors RT2, RT3, RT4, RT6, a capacitor CT10, a diode DT4 and a transistor QT2; Pin 1 of the front end of the optocoupler DT3 is electrically connected to a 5V power supply, a resistor RT6 and a capacitor CT10 are connected in parallel as a filter, one end of which is connected to a 5V power supply, and the other end and one end of the resistor RT4 are connected together to pin 2 of the optocoupler DT3, the other end of the resistor RT4 is connected to the positive electrode of the diode DT4, and the negative electrode of the diode DT is connected to the positive electrode R+ of the detection terminal; pin 3 of the rear end of the optocoupler DT3 is connected to DVDD, one end of the resistor RT3 connected in parallel with the resistor RT2 is connected to pin 4 of the optocoupler, the other end of the resistor RT2 is connected to the ground, the other end of the resistor RT3 is connected to the base of the transistor QT2, the collector of the transistor is connected to the power-on meter box detection signal MeterBox Cover Open Test P, and the emitter is connected to the ground; In the power-off detection circuit, The single chip computer signal input circuit includes resistors RT8-RT10, PMOS tube QT4, Y capacitor CT3 and unidirectional TVS tube DT2; One end of the resistor RT10 is connected to the microcontroller input signal MeterBox cover Open Test Ctl, and the other end is connected to the gate of the PMOS tube QT4 with one end of the resistor RT9. The other end of the resistor RT9 and MVDD are connected to the source of the PMOS tube QT4. The resistor RT8 is connected in parallel with the TVS tube DT2, and the positive electrode of the TVS tube DT2 is grounded. The negative electrode of the TVS tube DT2 and one end of the Y capacitor CT3 are connected to the drain of the PMOS tube QT4. The other end of the Y capacitor CT3 is connected to the detection electrode R+. The signal output circuit includes transistor QT1, resistor RT5, capacitors CT1, CT2 and diodes DT1, DT5; the cathode of diode DT5 is connected to MGND, and the anode of diode DT5 is electrically connected to air switch MB1 and one end of Y capacitor CT2 respectively; after resistor RT5 is connected in parallel with capacitor CT1, one end is connected to the base of transistor QT1 together with the cathode of diode DT1 and the other end of Y capacitor CT2, the other end of resistor RT5 is connected in parallel with capacitor CT1, the anode of diode DT1 and the emitter of transistor QT1 are connected to GND, and the collector of transistor QT1 is connected to the normally closed pin MeterBox cover Open Test NP of analog switch, and is pulled to a high level through the analog switch.

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